UNIT 3: The Cell Biology I DAYSHEET 28: Intro to Microscopy Name _____________________________________ Date: __________

Bellringer: Carefully analyze the data table below. Use the data to create a line graph. Be sure to include all of the following labels (Graph Title, x-axis label, y-axis label, and connect the dots/data points). Use two different colors to graph pepsin and trypsin. Affect of pH on Enzyme Function

pH Pepsin Trypsin 0 0 mol/sec 0 mol/sec 1 5 mol/sec 0 mol/sec 2 35 mol/sec 0 mol/sec 3 50 mol/sec 0 mol/sec 4 40 mol/sec 5 mol/sec 5 25 mol/sec 25 mol/sec 6 5 mol/sec 55 mol/sec 7 0 mol/sec 60 mol/sec 8 0 mol/sec 55 mol/sec 9 0 mol/sec 40 mol/sec

10 0 mol/sec 20 mol/sec 11 0 mol/sec 5 mol/sec 12 0 mol/sec 0 mol/sec

1. Name the enzyme that works best in highly acidic conditions: ___________________________

2. Name the enzyme that works best in less-acidic conditions: _____________________________

3. Identify the optimal pH for pepsin function: ___________________

4. Identify the optimal pH for trypsin function: __________________

5. If pepsin is only found in the stomach, what does the graph indicate about the relative acidity of the stomach? __________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________

Objective: I can determine total magnification of a microscope, create a wet-mount slide, and determine which microscope would be best suited for a laboratory. Homework: Complete HW28-Cell Theory Practice

Activity 1: Microscopy Cornell Notes

#1: What terminology (words) do scientists use when talking about microscopes?

#2: How do you calculate the power (magnification) of a microscope?

#3: What are the different types of microscopes?

#4: How do you prepare a specimen to look at under a microscope?

• _______________________________ = a technique used to increase the size

of a specimen (sample)

• _______________________________ = the size of an image

•

• ________________________________ = the clarity (clearness) of an image

• Power(Magnification) of Image = power of the __________________ X

power of the _______________________________

• We use the unit “______” (times larger) when describing the magnification.

• We can see __________________________________________ with higher

magnification, but we cannot see _________________________________

1) _______________________ microscope = light reflects off the surface of the

object; you can see the object with the naked eye (5X – 30X magnification)

2) _______________________ microscope = light shines through the object;

objects are too small to see with the naked eye (100X – 400X magnification)

3) _______________________ microscope = uses electrons to form an image of

an object; objects are VERY small (200,000x magnification)

1. Get a clean ____________ and ____________________________

2. Carefully place your __________________________ on the glass slide

3. Place one __________________________________ on top of your specimen

4. If your specimen is clear or hard to see, use a _______________

5. Slowly lower the coverslip on top of the specimen at a __________________

to prevent ____________________!

• Label the following in the above picture: enzyme, substrate, active site

Essential Questions Notes:

Name: Period: Date:

Biology Objective:

1. What would you use the above materials to make? ______ ___________ ___________ 2. How do you calculate the total magnification of a microscope image?

3. Evan is looking at a specimen under the microscope. His eye piece had a magnification of 10x and the lens he

was using had a magnification of 40x. What is the total magnification of Evan’s microscope? _______________

Summary: Answer the questions below

ructure of a water molecule by filling in the blanks below!

Essential Questions Notes:

#5: What are the parts of a microscope?

Activity 1: Making a Wet Mount Slide Directions: Follow the instructions to make a wet mount slide. When your table is called up to the microscope, focus your image using the instructions below. 1. Place the letter “e” slide on the stage so that the “e” looks upright to the naked eye and is positioned

over the hole on the stage. Without looking through the eyepiece, draw the letter “e” as it appears on the slide in the circle below.

2. Be sure that the low power objective is in place.

3. Open the diaphragm to give maximum light.

4. Use the coarse adjustment knob until the object comes into view.

5. Once the object is seen, it may be necessary to adjust the amount of light by adjusting the

diaphragm.

6. Use the fine adjustment knob to sharpen the focus. Do not over-use the fine adjustment.

7. Practice having both eyes open when looking through the eyepiece, as it greatly reduces eyestrain.

Draw the letter “e” as it appears when you look through the eyepiece and low power objective.

8. Switch to the medium power objective

9. Use the fine adjustment knob to sharpen the focus. Do not use the coarse adjustment.

10. Practice having both eyes open when looking through the eyepiece, as it greatly reduces eyestrain.

Draw the letter “e” as it appears when you look through the eyepiece

and medium power objective.

11. Switch to the high power objective

12. Use the fine adjustment knob to sharpen the focus. Do not use the coarse adjustment.

13. Practice having both eyes open when looking through the eyepiece, as it greatly reduces eyestrain.

Draw the letter “e” as it appears when you look through the eyepiece

and high power objective.

Activity 2: Practice Calculating Magnification

On this compound microscope, the eyepiece has a magnification of

10X. The low-powered objective lens has a magnification of 10X.

The medium-powered objective lens has a magnification of 20X.

The high-powered objective lens has a magnification of 40X.

Find the TOTAL MAGNIFICATION of each objective.

1. Low-powered objective

_____________ X ______________ = _____________

OBJECTIVE EYEPIECE TOTAL magnification magnification magnification

2. Medium-powered objective _____________ X ______________ = _____________ OBJECTIVE EYEPIECE TOTAL magnification magnification magnification

3. High-powered objective _____________ X ______________ = _____________ OBJECTIVE EYEPIECE TOTAL magnification magnification magnification

4. A student wants to view cells under the compound microscope at total magnification of 400X. If the

eyepiece is 10X, what power lens should the student use? ________________

5. A student views cells under a microscope at a total magnification of 1000X. If the lens has a magnification of 100X, what power magnification is the eyepiece? _________________

Directions: Label the parts of the microscope below using the words in the bank below:

STAGE FINE ADJUSTMENT COURSE ADJUSTMENT

EYEPIECE LIGHT SOURCE

Robert Hooke observed a thin slice of cork under a microscope and presented a drawing similar to the one shown. 1. What did Hooke call the small room-like structures he observed? 2. What is the approximate size of the cork sample on the left in the microscope image? 3. Robert Hooke’s microscope had a magnification of 400X. What is the actual size of the cork sample on the left?

5

Whywastheinventionofthemicroscopeimportant?

Wheredidthename“cell”comefrom?

Whatnewdiscoveriesweremadeinthe1800s?

Activity 3: Cell Reading – Use your Reading Strategies!

The History of the Cell Theory

The invention of microscopes made it possible for

scientists to view and study cells. Cells are the basic

units of living organisms. In the 1600s, a man named

Anton van Leeuwenhoek (LAY vun hook) used a

single lens microscope to view bacteria. Until then,

bacteria had never been seen! Later, compound

light microscopes used several lenses and could

magnify objects up to 1500 times their original size!

But where did we come up with the name “cell?” This

came about when the scientist Robert Hook looked at

thin slices of cork under a compound microscope.

Thinking the small shapes he saw looked like small

rooms, he called them cells!

By the 1800s, microscopes had been improved,

allowing scientists to make important observations.

First, Robert Brown, a Scottish scientist, discovered

that cells had an important inner compartment, called

the nucleus (NEW klee us). Later, two German

biologists, Matthias Schleiden and Theodor Schwann,

did their own experiments and learned that all living

things are made of one or more cells.

ABOVE:Apictureof

amicroscope,aninstrumentusedtoseeverysmall

thingsupclose.

Cells=thebasicunit,orbuilding

block,ofalllivingthings.

Whatarethe3partsofcelltheory?

Whatisanadvantageofelectronmicroscopes?

Whatdowecallthesmallstructuresinsideofcells?

What is the cell theory?

The experiments of Schleiden, Schwann, and

other scientists led to the development of what is called

the cell theory. It is one of the fundamental ideas of the

science of biology. The three main parts of the cell

theory are summarized below:

1. All living things are made of one or more cells.

2. Cells are the basic units of life.

3. All cells are produced by existing cells

How do microscopes help scientists learn about cells?

In the 1930s and 1940s, microscopes were

improved. Electron microscopes allowed scientists to

magnify an object up to 200,000 times using a beam of

electrons instead of a beam of light. Microscopes are

continually being improved so scientists can gather

more information about cells.

The Two Basic Cell Types

Using microscopes, scientists saw that all cells

contain small structures called organelles. Each

organelle has a specific function in the cell. Some cell

organelles are held together by membranes, and others

are not.

Schleiden,above,

andSchwann,below,madeveryimportant

discoveriesaboutcellsinthe19thcentury.

Whatareprokaryotes?

Whatareeukaryotes?

Whataresomedifferencesbetween

prokaryotesandeukaryotes?

Scientists group cells into two categories – cells that have membrane-bound

organelles and cells that do not. Cells that do not contain membrane-bound

organelles are called prokaryotes (pro kar ee AWTS). Unicellular organisms,

such as bacteria, are prokaryotes.

PROKARYOTIC CELL EUKARYOTIC CELL

If the cell has organelles that are held together by a membrane, the cell is

called a eukaryote (yew kar ee AWT). Most cells you can think of are eukaryotic.

These include most of the multi-cellular organisms that you know. Having

membrane-bound organelles is an advantage for eukaryotic cells because

chemical reactions in different parts of the cell can happen at the same time.

Other differences in prokaryotic and eukaryotic cells

While they do have a few things in common, there are many important

differences between prokaryotes and eukaryotes discussed below. Eukaryotic

cells have a central organelle called the nucleus that controls all of the cell’s

activities. This nucleus also holds the DNA of the cell. Prokaryotes do not have

an organized nucleus. Instead, they have loose strands of DNA. Prokaryotic cells

are also much smaller than eukaryotic cells. In addition, prokaryotic cells have

less “stuff” within the cell.

Homework 28: Cell Theory Practice Biology I Name: ______________________________________ Date: _________________ Directions: Match the scientists with their contribution to the Cell Theory. Matthias Schleiden -Invented the first microscope Antony von Leewenhoek -Stated that all animals are composed of cells. Francisco Redi -Disproved spontaneous generation with his meat and maggot experiment. Robert Hooke -Stated that all plants are composed of cells. Theodore Schwann -He was the first to see bacteria, sperm, microscopic worms, protists, and red blood cells. Zacharius Jenssen -He was the first to see the smallest unit of life and call them “cells” Directions: Answer the following essay question using complete sentences. What is the Cell Theory? ______________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________